Urokinase-type plasminogen activator (uPA) is a serine protease which has been implicated in various biological processes, including fibrinolysis, (Carmeliet et al., 1994, Nature 369:419-424; Carmeliet et al., 1996, Haemostasis 26:132-153; Pinsky et al., 1998, J. Clin. Invest. 102:919-928; Bugge et al., 1996, Proc. Natl. Acad. Sci. USA 93:5899-5904) angiogenesis, (Odekon et al., 1992, J. Cell, Physiol. 150:258-263; Bacharach et al., 1992, Proc. Natl. Acad. Sci. USA 89:10686; Pepper et al., 1990, J. Cell Biol. 111:743-755; Goldberg et al., eds., 1997, In: Regulation of Angiogenesis Birkhauser Verlag, Basel, pp. 391-411) neointima and aneurysm formation, (Clowes et al., 1990, Circ. Res. 67:61-67; Carmeliet et al., 1997, Circ. Res. 81:829-839; Shireman et al., 1997, J. Vasc. Surg. 25:157-164; Noda-Heiny et al., 1995, Arterioscler. Thromb. Vasc. Biol. 15:37-43; Lijnen et al., 1998, Arterioscler. Thromb. Vasc. Biol. 18:1035-1045) chemotaxis, (Pedersen et al., 1996, Br. J. Haematol. 95:45-51) and wound healing (Carmeliet et al., 1998, J. Cell Biol. 140:233-245).
Certain of these activities may require the proteolytic activity of uPA, (Kirschheimer et al., 1987, Fed. Am. Soc. of Exper. Biol. and Med. Journal 1:125-128; DePetro et al., 1994, Exp. Cell Res. 213:186-194) whereas others involve intracellular signaling through the urokinase receptor (uPAR) (Pedersen et al., 1996, Br. J. Haematol. 95:45-51; Degryse et al., 1999, Blood 94:649-662) or additional, as yet undefined receptors (Carmeliet et al., 1998, J. Cell Biol. 140:233-245; Kanse et al., 1997, Arteriosclerosis, Thromb., and Vas. Biol. 17:2848-2854; Koopman et al., 1998, J. Biol. Chem. 273:33267-33272; Rabbani et al., 1992, J. Biol. Chem. 267:14151-14156).
Urokinase is synthesized as a single chain molecule (scuPA) which exhibits little or no intrinsic enzymatic activity (Urano et al., 1988, Arch. Biochem. Biophys. 264:222-230; Gurewich et al., 1987, Semin. Thromb. Hemost. 13:146-151; Husain, 1991, Biochemistry 30:5707-5805). scuPA is a multi-domain protein composed of a C-terminal protease domain and an amino-terminal fragment (ATF). The ATF is composed of two domains: a growth factor domain (GFD) which binds to uPAR, and a kringle domain (uPA kringle), the function of which has heretofore been unknown. scuPA can be cleaved by plasmin at the Lys158-Ile159 position to generate an enzymatically active, disulfide-linked two-chain urokinase molecule (tcuPA). Between the ATF and the protease domain is a region designated the connecting peptide (corresponding to amino acids 136-158).
It is hypothesized that the natural enzyme uPA is normally used in the human body to dissolve clots and to facilitate cell migration. Although uPA is known in the art as a useful therapeutic molecule for the treatment of diseases and disorders having as a symptom thereof abnormal clotting in critical blood vessels, there remains a need in the art for compositions and methods which are useful for the treatment of such diseases as well as for the treatment of diseases and disorders having as symptoms abnormally high or abnormally low muscle cell contractility or undesirable angiogenic activity. Such diseases and conditions include the following: cardiovascular diseases and conditions such as hypotension, hypertension and atherosclerosis; thrombotic conditions such as stroke, heart attack and post angioplasty stenting; angiogenic disorders; respiratory diseases and conditions such as pulmonary fibrosis and asthma; diseases and disorders related to tumor cell invasion, angiogenesis and metastasis; wound healing and clotting disorders and reproductive disorders such as premature uterine contraction and impotence. The present invention meets these needs.